ONS Geography User Guide

ONS Postcode Directory (ONSPD)

From the February 2011 release, the ONS Postcode Directory (ONSPD) replaced the National Statistics Postcode Directory (NSPD). The ONSPD relates both current and terminated postcodes to a range of current statutory administrative, electoral, health and other geographies, as well as to some abolished and frozen geographies in the UK. The ONSPD is released quarterly.
Further Information about the ONSPD

Ordnance Survey

Ordnance Survey of Northern Ireland (OSNI)

The Land & Property Services (LPS) in Northern Ireland has incorporated the Ordnance Survey of Northern Ireland (OSNI) into its organisation and produces mapping with the OSNI branding.
Further information about LPS

Organisational Data Services (ODS)

The Organisational Data Services (ODS) supplies the codes for health geographies and organisation sites, such as hospitals and GP practices, in the UK. The ODS provide codes that are distributed to the wider NHS and loaded onto its IT systems, which in turn means that locations can be identified quickly and correctly.
Further information about the ODS

OS MasterMap®

OS MasterMap® is Ordnance Survey's intelligent digital map of Great Britain. It contains a wide range of different layers of mapping data and is designed for use with Geographic Information Systems (GIS) and database systems. OS MasterMap® is the branded product of the Digital National Framework (DNF).
Further information on Ordnance Surveys Mastermap

Outer London

Outer London refers to the part of Greater London falling outside the boundaries of the former London county, which existed from 1889 to 1965. The outer London area includes 19 of the London boroughs.
Further information on London boroughs

Output Area (OA)

Output Areas (OA) are used across the UK as the base unit of census output. They were introduced in Scotland in 1991 and the rest of the UK in 2001. They superseded Census enumeration districts (ED), although EDs are still used for census data collection.
Further information on the UK Census and census geography